Computing Device Hinge Assembly With Dual Friction Bands

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Solution Overview

Problem

Existing foldable computing devices with hinges experience uneven torque application on shafts, leading to mismatched rotation rates of displays, undesirable user experience, and uneven wear on gear surfaces.

Innovation Solution

A hinge assembly with first and second hinge brackets, each equipped with drive gears and shafts, and idler gears, utilizing first and second friction bands that apply torque in opposite directions to balance torque on the drive gear shafts, ensuring synchronized rotation and uniform wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single friction band is used to apply torque to the drive gear shafts, then the structure is simpler, but the torque distribution becomes uneven causing mismatched rotation rates

Engineering Contradiction:
Improvehinge assembly structureVSAvoidtorque distribution uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The single friction band is divided into two separate friction bands (first friction band and second friction band), each independently applying torque to opposite sides of the drive gear shafts. This segmentation allows each friction band to be positioned and biased independently, achieving balanced torque distribution across both shafts while maintaining relatively simple individual band structures.

Inventive Principle:
Principle #1Segmentation

2Duration of action of stationary object

If friction bands are made adjustable to compensate for wear and misalignment, then component life is extended, but the mechanism becomes more complex

Engineering Contradiction:
Improvecomponent service lifeVSAvoidfriction band mechanism
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The friction bands are designed with adjustable biasing forces that can be dynamically modified during the device's operation. The biasing portions can be adjusted to compensate for wear on the friction band contacting surfaces and misalignment between the friction bands and drive gear shafts, allowing the system to maintain optimal torque distribution throughout its service life without requiring complex replacement mechanisms.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides balanced torque distribution, reducing gear backlash, extending component life, and offering a consistent user experience by compensating for wear and misalignment over time.

Implementation Method 1

A first friction band comprises a first arcuate contacting surface, an opposing second arcuate contacting surface, and a first biasing portion between the first arcuate contacting surface and the second arcuate contacting surface. The first biasing portion is biased in a first direction to press the first arcuate contacting surface against a first portion of the first drive gear shaft and the second arcuate contacting surface against a third portion of the second drive gear shaft.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4466586B1Computing device hinge assembly
Publication Date: 2025.08.27 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4466586B1 patent drawingFigure 1~2
  • EP4466586B1 patent drawingFigure 3
  • EP4466586B1 patent drawingFigure 4

AI summary

A hinge assembly for rotatably coupling first and second substrates of a computing device comprises first and second hinge brackets affixed to the first and second substrates, with each bracket including a drive gear and shaft. First and second idler gears engage the drive gears. A first friction band comprises a first biasing portion that is biased in a first direction to press a first arcuate contacting surface of the first friction band against the first drive gear shaft and a second arcuate contacting surface against the second drive gear shaft. A second friction band comprises a second biasing portion that is biased in a second direction to press a third arcuate contacting surface of the second friction band against the first drive gear shaft and a fourth arcuate contacting surface against the second drive gear shaft.